In recent years, with regard to fragrance materials, it has been desired to develop a new fragrance material not only having unique and excellent fragrance characteristics but also exhibiting excellent secondary physical properties such as stability to base materials and light stability owing to the increasing diversification of fragrant cosmetics. Particularly, the development of a distinctive fruity floral new fragrance material has been highly requested by fragrances.
During the development of new fragrance materials, the present inventors have found that, when an alkaline material such as soap is mixed with optically active 1-(2,2,6-trimethylcyclohexyl)-2-buten-1-one which is a fruity floral fragrance hitherto widely used, the fragrance of the soap is deteriorated or degraded with time and the color of the soap changes in the case that the soap is exposed to light. In the course of devising a measure to solve these problems, they have noticed that, when a material such as soap is mixed with a geometrical isomer composition containing about 99% by weight of optically active trans-1-(2,2,6-trimethylcyclohexyl)-2-buten-1-one {optical isomer ratio: (1R,6S)-isomer/(1S,6R)-isomer=99/1}, the fragrance of the soap is hardly deteriorated or degraded with time and the color of the soap hardly changes in the case that the soap is exposed to light.
Thus, an object of the invention is to provide a fragrance composition having unique fruity floral fragrance and exhibiting excellent secondary physical properties such as stability to base materials and light stability. Particularly, it is to provide an isomer composition excellent in chemical resistance, which is applicable to a base material containing a strong alkaline chemical or a strong acidic chemical, which can suppress the deterioration or degradation of fragrance with time and the color change of the base material in the case that the material is exposed to light, and which also have highly palatable and unique fruity floral fragrance.